Paper
18 December 1992 A high sensitivity real-time NVR monitor
William D. Bowers, Raymond L. Chuan
Author Affiliations +
Abstract
The use of a temperature-controlled 200-MHz SAW resonator piezoelectric mass microbalance to monitor the mass of nonvolatile residue (NVR) deposited on its surface in real time is reported. The fundamental frequency of this device is mainly dependent on the configuration of the transducers and not on the thickness of the substrate. Therefore, higher operating frequencies can be achieved without reducing the thickness of the crystal. The real-time instrument was integrated onto a conventional stainless steel NVR plate and operated flawlessly over a 14-d period at Kennedy Space Center and successfully measured less than 1 ng/sq cm d NVR contamination. Contamination episodes detected by the instrument were correlated with scheduled activities on the test stand. Under the assumption of a baseline noise level of +/- 2 Hz, the absolute mass lower limit of detection would be 0.065 ng/sq cm. This would enable the detection of a daily NVR deposition rate of less than 0.1 ng/sq cm d.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
William D. Bowers and Raymond L. Chuan "A high sensitivity real-time NVR monitor", Proc. SPIE 1754, Optical System Contamination: Effects, Measurement, Control III, (18 December 1992); https://doi.org/10.1117/12.140745
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KEYWORDS
Crystals

Contamination

Resonators

Transducers

Space operations

Sensors

Reflectors

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